1. Field of the Invention
The present invention relates to methods for manufacturing printed circuit boards (PCBs) and, particularly, to a method for manufacturing a multilayer printed circuit board having buried holes.
2. Description of Related Art
Multilayer PCBs are composed of a number of single-sided PCBs and/or double-sided PCBs. Multilayer PCBs have holes to electrically connect adjacent traces. In order to accommodate to the integration and miniaturization of electronic components, buried holes have been designed to electrically connect adjacent traces and to reduce an area of the traces.
A conventional build-up method for manufacturing multilayer PCBs having buried holes includes the following steps. In a first step, a first single-sided PCB is provided. The first single-sided PCB includes a first insulation layer and a first circuit formed on the insulation layer. In a second step, a copper clad laminate including a second insulation layer and a copper layer is provided, and the second insulation layer of the copper clad laminate is laminated on the first circuit of the first single-sided PCB. In a third step, a second circuit is formed on the copper layer, and a first through hole communicating with the first circuit and the second circuit is also formed in the second insulation layer. Thus, a multilayer PCB having two layers of circuits is fabricated. The second and third steps are repeated and a multilayer PCB having predetermined layers of circuits is fabricated. However, regarding the above manufacturing method of the multilayer PCB, a laminating process is required to be performed in each of the repeated second steps, thereby complicates the manufacturing process.
What is need, therefore, is a method for manufacturing multilayer PCB which can overcome the above shortcomings.